This invention relates to deadbolts or locks for securing doors and the like, and will be disclosed herein in its adaptation to automobile doors and subject to the operation of that type of vehicle. It is a general object of this invention to provide security, and for example to prevent access or "breaking of the close" and alternately to permit access for ingress and egress. Heretofore, most locks have been key operated or combination operated, with mechanical limitations on key distinction and/or combination, and consequently subject to insecurity. That is, lock tumbler positioning can be determined by outsiders, or thieves and the like, and pass keys are available; all to the end that mechanical lock security is restricted and not entirely reliable. A state of the art locking device of the type under consideration utilizes electronics for the release of a deadbolt, as disclosed in U.S. Pat. No. 3,733,861 issued to Robert W. Lester May 23, 1973 and entitled Electronic Recognition Door Lock, wherein a transponder transmits a range of ultrasonic signals of varying frequency, which equal a code sequentially both in time length and frequency. The three sequential timed signals are received by transducers and transmitted to a shift register that activates a bolt releasing solenoid, only after signals are received in the proper sequence. The Lester system is feasible but is unecessarily complicated and restrictive through its indirect mode of operation, and therefore not entirely practical. Accordingly, it is an object of this invention to provide an improved electronic security system having a direct mode of operation over locked devices and closures, whereby the lock closing and opening combinations are not only unpredictable but are substantially increased in number of combinations available for greater security; each combination herein being distinctly a "passive code".
State of the art electronics and electric actuation and control apparatus as well as a power source therefor are all extremely reliable and the operation thereof predictable. It is an object therefore to employ electronics and its associated means of employment as a securement where locks and the like are usually employed. With the present invention, passive electronic coding replaces sequentially timed coding and mechanical devices and/or combination means, greatly simplifying and substantially increasing reliability and the finite choice of so-called opening combinations. As will be described, one or more and preferably a plurality of frequencies in the form of a passive code are simultaneously encoded and decoded, each frequency referred to herein as a "tone" which may extend beyond human hearing and distinct frequencies thereof selected within bands at close intervals for finite coding.
An actively occupied dwelling or vehicle can be expected to have a readily available and reliable power source, namely electrical power. It is therefore and object of this invention to employ available electrical power as the force to exclusively operate the electronics and motivation of the lock or deadbolt as it is disclosed herein. The wiring and control unit installations are readily secreted so as to be inaccessible to the would-be intruder, and operational reliability is ensured by readily available high quality electronics and associated electrical components installed in a tamperproof manner. Accordingly, the system of the present invention is entirely electronic and/or electrical and in no instance can the circuits be preempted and the lock or deadbolt defeated.
The operation of a lock involves closing and opening, and since this invention is concerned particularly with exclusive electrical actuation, both the closing and opening modes of operation are controlled thereby. Therefore, it is an object of this invention to provide distinct opening and closing codes, to provide cooperative encoding and decoding of both codes, and all of which is associated with control switching of motor means by which the lock or deadbolt is driven to a closed or an opened position.
Safe operation of a vehicle requires door egress at any time, for example in case of an emergency. Therefore, it is an object of this invention to preempt the locking condition through the vehicle operation; and in this disclosure by the actuation of the auto ignition switch to the "ON" position. Thus, while the vehicle is operating, the deadbolt is maintained in the opened condition, and alternately when the vehicle is out of operation and the ignition switch "OFF", the deadbolt is conditioned so that it can be closed. Opening is assured by the ignition switch being "ON", while closing is passive and permitted by the ignition switch being "OFF".
It is also an object of this invention to provide for any failure of the deadbolt penetration into the bolt hole or door jamb. To this end, a pressure sensing means is proivded which is associated with control and limit switches that cooperate with the decode switch as will be described.